Wideband radial line slot array antenna

Abstract

An antenna includes a waveguide defined by a gap between a backplane with radial support ribs and a facesheet, a teardrop-shaped feed pin at a center of the backplane, and a foam spacer between the backplane and facesheet. An outward facing side of the facesheet includes thermal paint. The facesheet includes pairs of through-hole slots for releasing portions of a wave of radiation in the waveguide to generate a transmit-beam or to receive the receive-beam to generate the wave of radiation. The pairs may be disposed as a spiral array about a center of the facesheet. Each of the pairs may include first and second slots. A length of the second slot is oriented approximately perpendicular to a length of the first slot. Dispositions of the slots are set by a computer process. The dispositions optimize a trade-off between transmit and receive gains.

What is claimed is: 
     
       1. An antenna comprising:
 a waveguide configured to transmit a transmit-beam of radiation and receive a receive-beam of radiation, the waveguide comprising:
 a backplane comprising radial support ribs; 
 a feed pin comprising a teardrop shape and disposed at a center of the backplane and configured to interact with a wave of radiation; 
 a foam spacer disposed on the backplane, wherein an effective refractive index of the waveguide with the foam spacer is greater than approximately 1.0 and less than approximately 1.5; 
 a facesheet disposed on the foam spacer and opposite to the backplane  104  to allow the wave of radiation to propagate between the backplane and the facesheet and through the foam spacer, the facesheet comprising:
 thermal paint disposed on an outward-facing side of the facesheet; and 
 pairs of through-hole slots configured to release portions of the wave of radiation to generate the transmit-beam or to receive the receive-beam to generate the wave of radiation, wherein the pairs are disposed as a spiral array about a center of the facesheet and each of the pairs comprises:
 a first slot having a length and a width; and 
 a second slot having a length and a width, wherein the length of the second slot is oriented approximately perpendicular to a length of the first slot, 
 
 
 
 wherein dispositions of the pairs of through-hole slots are set by a computer process using spline interpolation of parameters of the antenna and are configured to optimize or maximize trade-off between transmit and receive gains associated with the transmit-beam and receive-beam. 
 
     
     
       2. The antenna of  claim 1 , wherein the backplane and facesheet each have a circular shape. 
     
     
       3. The antenna of  claim 1 , wherein the feed pin is disposed between the backplane and the facesheet and is proximal to the center of the facesheet. 
     
     
       4. The antenna of  claim 1 , wherein the transmit-beam and the receive-beam have different frequencies from each other that define a wide bandwidth greater than approximately 0.1 GHz and less than approximately 100 GHz. 
     
     
       5. The antenna of  claim 1 , wherein the transmit-beam and the receive-beam have different frequencies from each other that define a wide bandwidth greater than approximately 7.2 GHz and less than approximately 8.4 GHz. 
     
     
       6. The antenna of  claim 1 , wherein the pairs of through-hole slots are disposed to maximize a combination of the transmit and receive gains in accordance with an industry standard. 
     
     
       7. The antenna of  claim 1 , wherein
 the backplane comprises aluminum, and 
 the facesheet comprises aluminum. 
 
     
     
       8. The antenna of  claim 1 , wherein the feed pin comprises gold plated beryllium copper. 
     
     
       9. The antenna of  claim 1 , wherein
 the foam spacer comprises a dielectric material, and 
 the effective refractive index is greater than approximately 1.0 and less than approximately 1.5. 
 
     
     
       10. The antenna of  claim 1 , further comprising:
 a connector coupled to the feed pin; and 
 a shim disposed between the connector and the backplane, the shim comprising a hole to allow the feed pin to be inserted through the backplane.